Implantable electrical signal generators, such as pacemakers, defibrillators, neurostimulators, and the like, have been used to treat a variety of diseases. Such devices generate electrical signals that are transferred to a patient's tissue through electrodes present on a distal end portion of a lead. The proximal end portion of a lead, connected to a signal generator, typically contains a number of connector rings corresponding to the number of electrodes. Conductors, also referred to as wire filars or merely filars, run within and along the lead body and electrically couple the connectors to the electrodes.
One particular type of implantable device is an implantable neurological stimulation system that can be used to treat conditions such as pain, movement disorders, pelvic floor disorders, gastroparesis, and a wide variety of other medical conditions. The neurostimulation system typically includes a neurostimulator, a stimulation lead, and an optional lead extension. As an example, the neurostimulator system can be an Itrel II™ Model 7424 or an Itrel 3™ Model 7425 available from Medtronic, Inc., in Minneapolis, Minn., that can be used to treat conditions such as pain, movement disorders and pelvic floor disorders. The neurostimulator is typically connected to a stimulation lead that has one or more electrodes to deliver electrical stimulation to a specific location in the patient's body.